Sorry, the title might be a bit confusing: what I mean is, actors who have portrayed different comic/superhero characters in different films (as opposed to, say, Hugh Jackman reprising the Wolverine role in multiple films).
The examples I can think of off the top of my head so far:
Halle Berry: Storm (X-Men films) and Catwoman (Catwoman)
Keanu Reeves: John Constantine (Constantine) and, arguably, Neo (Matrix films)
Chris Evans: Johnny Storm (Fantastic 4 movies), Captain America (Avengers films)
Will Smith: Jay (Men in Black films), John Hancock (Hancock)
Kristy Swanson: Supergirl, Diana Palmer (The Phantom)
Ryan Reynolds (THREE different roles!): Hannibal King (Blade Trinity), Hal Jordan (Green Lantern), Wade Wilson (X-Men Origins: Wolverine)
Any others you can think of?
Aaron Taylor-Johnson: Kick-Ass (Kick-Ass), Quicksilver (Avengers: Age of Ultron)
Arnold Schwarzeneggar: Mr. Freeze (Batman & Robin), Conan (Conan the Barbarian, Conan the Destroyer)
Gary Oldman: Jim Gordon (Nolan’s Batman movies), Dr. Norton (RoboCop)
Well, there are several comics based on the character, but I don’t think it originated as one; same with G.I.Joe, Conan, and others, but I think if you have a character that gets his or her own comic series (as opposed to a limited series “movie adaptation” comic) it could count.
Also, the superhero bit opens up the possibility for non-comics superheroes, like Hancock.